Edgar Anderson’s Iris Data
Description
This famous (Fisher’s or Anderson’s) iris data set gives the measurements in centimeters of the variables sepal length and width and petal length and width, respectively, for 70 flowers from each of 3 species of iris. The species are Iris setosa, versicolor, and virginica.
Source
Fisher, R. A. (1937) The use of multiple measurements in taxonomic problems. Annals of Eugenics, 7, Part II, 179–188. The data were collected by Anderson, Edgar (1937). The irises of the Gaspe Peninsula, Bulletin of the American Iris Society, 79, 2–7
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole. (has iris3 as iris.)
Examples (from R)
dni3 <- dimnames(iris3)
ii <- data.frame(matrix(aperm(iris3, c(1,3,2)), ncol = 4,
dimnames = list(NULL, sub(" L.",".Length", sub(" W.",".Width", dni3[[2]])))), Species = gl(3, 50, labels = sub("S", "s", sub("V", "v", dni3[[3]])))) all.equal(ii, iris) # TRUE
Motor Trend Car Road Tests
Description
The data was extracted from the 1974 Motor Trend US magazine, and comprises fuel consumption and 10 aspects of automobile design and performance for 32 automobiles (1973–74 models).
Note
Henderson and Velleman (1981) comment in a footnote to Table 1: ‘Hocking [original transcriber]’s noncrucial coding of the Mazda’s rotary engine as a straight six-cylinder engine and the Porsche’s flat engine as a V engine, as well as the inclusion of the diesel Mercedes 240D, have been retained to enable direct comparisons to be made with previous analyses.’
Source
Henderson and Velleman (1981), Building multiple regression models interactively. Biometrics, 37, 391–411.
Results from an Experiment on Plant Growth
Description
Results from an experiment to compare yields (as measured by dried weight of plants) obtained under a control and two different treatment conditions.
Format
A data frame of 30 cases on 2 variables.
[, 1] weight numeric
[, 2] group factor
The levels of group are ‘ctrl’, ‘trt1’, and ‘trt2’.
Source
Dobson, A. J. (1983) An Introduction to Statistical Modelling. London: Chapman and Hall.
Examples (from R)
## One factor ANOVA example from Dobson’s book, cf. Table 7.4: require(stats); require(graphics)
boxplot(weight ~ group, data = PlantGrowth, main = "PlantGrowth data", ylab = "Dried weight of plants", col = "lightgray",
notch = TRUE, varwidth = TRUE)
anova(lm(weight ~ group, data = PlantGrowth))
The Effect of Vitamin C on Tooth Growth in Guinea Pigs
Description
The response is the length of odontoblasts (cells responsible for
tooth growth) in 60 guinea pigs. Each animal received one of three
dose levels of vitamin C (0.5, 1, and 2 mg/day) by one of two delivery methods, orange juice or ascorbic acid (a form of vitamin C and coded as VC).
Format
A data frame with 60 observations on 3 variables.
[,1] len numeric Tooth length
[,2] supp factor Supplement type (VC or OJ).
[,3] dose numeric Dose in milligrams/day
Source
C. I. Bliss (1952). The Statistics of Bioassay. Academic Press.
References
- McNeil, D. R. (1977). Interactive Data Analysis. New York: Wiley.
- Crampton, E. W. (1947). The growth of the odontoblast of the incisor teeth as a criterion of vitamin C intake of the guinea pig. The Journal of Nutrition, 33(5), 491–504. doi: 10.1093/jn/33.5.491.
Examples
require(graphics)
coplot(len ~ dose | supp, data = ToothGrowth, panel = panel.smooth, xlab = "ToothGrowth data: length vs dose, given type of supplement")
Violent Crime Rates by US State
Description
This data set contains statistics, in arrests per 100,000 residents,
for assault, murder, and rape in each of the 50 US states in 1973.
Also given is the percent of the population living in urban areas.
Note
USArrests contains the data as in McNeil’s monograph. For the UrbanPop percentages, a review of the table (No. 21) in the Statistical
Abstracts 1975 reveals a transcription error for Maryland (and that
McNeil used the same “round to even” rule that R’s round() uses), as
found by Daniel S Coven (Arizona).
See the example below on how to correct the error and improve accuracy
for the ‘<n>.5’ percentages.
Source
World Almanac and Book of facts 1975. (Crime rates).
Statistical Abstracts of the United States 1975, p.20, (Urban rates), possibly available as
https://books.google.ch/books?id=zl9qAAAAMAAJ&pg=PA20.
References
McNeil, D. R. (1977) Interactive Data Analysis. New York: Wiley.
Examples
(summary usarrests)
;; Difference between ’USArrests’ and its correction
(which usarrests:x3 :predicate (lambda (x) (string= "Maryland" x))) ; #(19) (select usarrests 19 ’urbanpop) ; 67, the value transcribed incorrectly (setf (elt usarrests:urbanpop 19) 76.6) ; change to the correct value
;; correct rounding errors of +/- 0.5 to restore the original <n>.5 percentages (map nil (lambda (x)
(setf (elt usarrests:urbanpop x)
(+ 0.5 (elt usarrests:urbanpop x))))
(which usarrests:x3 :predicate (lambda (x)
(or (string= "Colorado" x)
(string= "Florida" x)
(string= "Mississippi" x)
(string= "Wyoming" x)))))
(map nil (lambda (x)
(setf (elt usarrests:urbanpop x)
(- 0.5 (elt usarrests:urbanpop x))))
(which usarrests:x3 :predicate (lambda (x)
(or (string= "Nebraska" x)
(string= "Pennsylvania" x)))))
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